A "Missing" Supernova Remnant revealed by the 21-cm Line of Atomic Hydrogen

Although some 20--30,000 supernova remnants (SNRs) are expected to exist in the Milky Way, only about 230 are presently known. This implies that most SNRs are ``missing''. Recently, we proposed that small (\simlt 1^\circ), faint, high-velocity features seen in large-scale 21-cm line surveys of atomic hydrogen ({\sc Hi}) in the Galactic plane could be examples of such {\it missing} old SNRs. Here we report on high-resolution \schi observations of one such candidate, FVW 190.2+1.1, which is revealed to be a rapidly expanding ($\sim 80$ \kms) shell. The parameters of this shell seem only consistent with FVW 190.2+1.1 being the remnant of a SN explosion that occurred in the outermost fringes of the Galaxy some $\sim 3\times 10^5$ yr ago. This shell is not seen in any other wave band suggesting that it represents the oldest type of SNR, that which is essentially invisible except via its \schi line emission. FVW 190.2+1.1 is one of a hundred "forbidden-velocity wings" (FVWs) recently identified in the Galactic plane, and our discovery suggests that many of these are likely to be among the oldest SNRs. We discuss the possible link between FVWs and fast-moving atomic clouds in the Galaxy.Comment: 12 pages, 3 figures, To appear in The Astrophysical Journal Letter

Numerical Simulation and Experiments for Dynamic Material Properties of Aluminium Alloy in SHPB Experiment using Pulse Shaping Method

For the analysis of high speed forming such as electromagnetic forming and electrohydraulic forming, dynamic material properties are required. The split Hopkinson pressure bar (Kolsky bar) was suggested for measuring dynamic material properties from 100 to 10000 /sec strain rate. In the SHPB experiments, the assumption is needed that specimen between incident bar and transmitted bar reaches the dynamic stress equilibrium. For the derivation of average engineering strain and average engineering stress in SHPB experiments, the stress wave at the front and the back of specimen should match each other. A pulse shaping method helps to improve the stress equilibrium of specimen. As one of the various pulse shaping methods, a method of attaching a pulse shaper in front of incident bar was carried out. Numerical simulation and SHPB experiments was performed for verification about pulse shaper effect. The result of experiments and numerical analysis show that the pulse shaper contributes to the dynamic stress equilibrium. The dynamic material properties of Al6061-T6 were obtained, and the simulation was implemented by inputting that properties. As a result of comparing the experiments with new simulation, it was confirmed that the error of specimen length was within 5%

Spin Fluctuation and Persistent Current in a Mesoscopic Ring Coupled to a Quantum Dot

We investigate the persistent current influenced by the spin fluctuations in a mesoscopic ring weakly coupled to a quantum dot. It is shown that the Kondo effect gives rise to some unusual features of the persistent current in the limit where the charge transfer between two subsystems is suppressed. Various aspects of the crossover from a delocalized to a localized dot limit are discussed in relation with the effect of the coherent response of the Kondo cloud to the Aharonov-Bohm flux.Comment: 4 pages, 2 figure

Variable stars in the Open Cluster M11 (NGC 6705)

V-band time-series CCD photometric observations of the intermediate-age open cluster M11 were performed to search for variable stars. Using these time-series data, we carefully examined light variations of all stars in the observing field. A total of 82 variable stars were discovered, of which 39 stars had been detected recently by Hargis et al. (2005). On the basis of observational properties such as variable period, light curve shape, and position on a color-magnitude diagram, we classified their variable types as 11 delta Scuti-type pulsating stars, 2 gamma Doradus-type pulsating stars, 40 W UMa-type contact eclipsing binaries, 13 Algol-type detached eclipsing binaries, and 16 eclipsing binaries with long period. Cluster membership for each variable star was deduced from the previous proper motion results (McNamara et al. 1977) and position on the color-magnitude diagram. Many pulsating stars and eclipsing binaries in the region of M11 are probable members of the cluster.Comment: 23 pages, 9 figures, 3 tables, and accepted for publication in PAS

Chemical Analysis of a Diffuse Cloud along a Line of Sight Toward W51: Molecular Fraction and Cosmic-Ray Ionization Rate

Absorption lines from the molecules OH+, H2O+, and H3+ have been observed in a diffuse molecular cloud along a line of sight near W51 IRS2. We present the first chemical analysis that combines the information provided by all three of these species. Together, OH+ and H2O+ are used to determine the molecular hydrogen fraction in the outskirts of the observed cloud, as well as the cosmic-ray ionization rate of atomic hydrogen. H3+ is used to infer the cosmic-ray ionization rate of H2 in the molecular interior of the cloud, which we find to be zeta_2=(4.8+-3.4)x10^-16 per second. Combining the results from all three species we find an efficiency factor---defined as the ratio of the formation rate of OH+ to the cosmic-ray ionization rate of H---of epsilon=0.07+-0.04, much lower than predicted by chemical models. This is an important step in the future use of OH+ and H2O+ on their own as tracers of the cosmic-ray ionization rate.Comment: 21 pages, 1 figure, 4 table

RACE-OC Project: Rotation and variability in the open cluster M11 (NGC6705)

Rotation and magnetic activity are intimately linked in main-sequence stars of G or later spectral types. The presence and level of magnetic activity depend on stellar rotation, and rotation itself is strongly influenced by strength and topology of the magnetic fields. Open clusters represent especially useful targets to investigate the rotation/activity/age connection. The open cluster M11 has been studied as a part of the RACE-OC project (Rotation and ACtivity Evolution in Open Clusters), which is aimed at exploring the evolution of rotation and magnetic activity in the late-type members of open clusters with different ages. Photometric observations of the open cluster M11 were carried out in June 2004 using LOAO 1m telescope. The rotation periods of the cluster members are determined by Fourier analysis of photometric data time series. We further investigated the relations between the surface activity, characterized by the light curve amplitude, and rotation. We have discovered a total of 75 periodic variables in the M11 FoV, of which 38 are candidate cluster members. Specifically, among cluster members we discovered 6 early-type, 2 eclipsing binaries and 30 bona-fide single periodic late-type variables. Considering the rotation periods of 16 G-type members of the almost coeval 200-Myr M34 cluster, we could determine the rotation period distribution from a more numerous sample of 46 single G stars at an age of about 200-230 Myr and determine a median rotation period P=4.8d. A comparison with the younger M35 cluster (~150 Myr) and with the older M37 cluster (~550 Myr) shows that G stars rotate slower than younger M35 stars and faster than older M37 stars. The measured variation of the median rotation period is consistent with the scenario of rotational braking of main-sequence spotted stars as they age.Comment: Accepted by Astronomy and Astrophysics on Dec 15, 200

Ten-Year Trends of Utilizing Palliative Care and Palliative Procedures in Patients With Gastric Cancer in the United States From 2009 to 2018 - A Nationwide Database Study

Objectives: Little is known about the current status and the changing trends of hospitalization and palliative care consultation of patients with gastric cancer in the United States. The aim of this study was to evaluate the changing trend in the number of hospitalization, palliative care consultation, and palliative procedures in the US during a recent 10-year period using a nationwide database. Methods: This was a retrospective study that analyzed the National Inpatient Sample (NIS) database of 2009–2018. Patients aged more than 18 years who were diagnosed with a gastric cancer using International Classification of Diseases (ICD)-9 and 10 codes were included. Palliative care consultation included palliative care (ICD-9, V66.7; ICD-10, Z51.5) and advanced care planning (ICD-9, V69.89; ICD-10, Z71.89). Palliative procedures included percutaneous or endoscopic bypass, gastrostomy or enterostomy, dilation, drainage, nutrition, and irrigation for palliative purpose. Results and discussion: A total of 86,430 patients were selected and analyzed in this study. Using a compound annual growth rate (CAGR) approach, the annual number of hospitalizations of gastric cancer patients was found to be decreased during 2009–2018 (CAGR: -0.8%, P = 0.0084), while utilization rates of palliative care and palliative procedures increased (CAGR: 9.3 and 1.6%, respectively; P \u3c 0.0001). Multivariable regression analysis revealed that palliative care consultation was associated with reduced total hospital charges (−$34,188, P \u3c 0.0001). Conclusion: Utilization of palliative care consultation to patients with gastric cancer may reduce use of medical resources and hospital costs

Pembrolizumab alone or in combination with chemotherapy as first-line therapy for patients with advanced gastric or gastroesophageal junction adenocarcinoma: results from the phase II nonrandomized KEYNOTE-059 study

BACKGROUND: The multicohort, phase II, nonrandomized KEYNOTE-059 study evaluated pembrolizumab ± chemotherapy in advanced gastric/gastroesophageal junction cancer. Results from cohorts 2 and 3, evaluating first-line therapy, are presented. METHODS: Patients ≥ 18 years old had previously untreated recurrent or metastatic gastric/gastroesophageal junction adenocarcinoma. Cohort 3 (monotherapy) had programmed death receptor 1 combined positive score ≥ 1. Cohort 2 (combination therapy) received pembrolizumab 200 mg on day 1, cisplatin 80 mg/m2 on day 1 (up to 6 cycles), and 5-fluorouracil 800 mg/m2 on days 1-5 of each 3-week cycle (or capecitabine 1000 mg/m2 twice daily in Japan). Primary end points were safety (combination therapy) and objective response rate per Response Evaluation Criteria in Solid Tumors version 1.1 by central review, and safety (monotherapy). RESULTS: In the combination therapy and monotherapy cohorts, 25 and 31 patients were enrolled; median follow-up was 13.8 months (range 1.8-24.1) and 17.5 months (range 1.7-20.7), respectively. In the combination therapy cohort, grade 3/4 treatment-related adverse events occurred in 19 patients (76.0%); none were fatal. In the monotherapy cohort, grade 3-5 treatment-related adverse events occurred in seven patients (22.6%); one death was attributed to a treatment-related adverse event (pneumonitis). The objective response rate was 60.0% [95% confidence interval (CI), 38.7-78.9] (combination therapy) and 25.8% (95% CI 11.9-44.6) (monotherapy). CONCLUSIONS: Pembrolizumab demonstrated antitumor activity and was well tolerated as monotherapy and in combination with chemotherapy in patients with previously untreated advanced gastric/gastroesophageal junction adenocarcinoma